In the art of building green tires, the present invention relates to a method and apparatus for supplying tire constituent material in the form of a belt in or by which it is possible to take-up on a building drum and splice tire constituent material efficiently and accurately without a reliance on the skill of operators or workers.
When winding and splicing tire constituent materials on a building drum, conventionally it has been practiced to take out materials from a servicer rack, locate tips of the taken-out materials to a predetermined position on the building drum, press the materials to tack on the building drum, turn the building drum a full turn so as to wind the materials thereon, cut the tips of the materials by a knife or a pair of scissors in a manner such that they are in agreement with the ends of the materials after cutting, press-splice one of the end portions of the material to the tips of the materials which are wound on the building drum, and fold back the other end portions of the material to the service rack.
Therefore, the work of rapidly and accurately locating tips of taken-out materials to the predetermined position on the building drum depends greatly upon the skill of the worker, and the speed of the work as well as the accuracy in locating depend greatly upon the worker's skill.
Also, with the material cutting work, it is extremely difficult to determine the position for cutting so that the overlap quantity of the material joint portion becomes appropriate. Therefore, the work speed varies greatly, and variations occur in the cutting length of the materials. When, for example, the cut length is short, the portion near the joint portion is locally extended and spliced, while the overlap quantity of the joint portion will become excessive if the cut length is excessively great. Thus, non-uniformity occurs in the resulting tire.
Further, it is also difficult to accurately linearly cut wide materials such as an innerliner throughout its width, and non-uniformity is likely to occur at the joint portion.
For above described reasons, the accuracy at which tire constituent materials are wound up on the tire building drum and spliced has to depend on the skill of the worker, and the work speed varies from a worker to another, so that an improvement in or relating to the quality and the production efficiency of tires can hardly be attained.
In order to solve the problems, various apparatus have heretofore been proposed which automatically supply tire constituent materials to the building drum. However, all of the proposed apparatus are great in scale or size since they include an automatic cutter, a device for press-splicing the materials to the building drum, and so forth. Therefore, they involve a great space requirement, cannot be assembled in a multiple-stage arrangment and are extremely expensive to build.
On the other hand, the splicing accuracy is not sufficiently high at present for those constituent materials such as a carcass which requires a high splicing accuracy and for those relatively thick constituent materials equipped with a profile such as a side wall, a rim cushion, and so forth, because the work accuracy of the materials is not high or because the materials undergo deformation such as elongation. Accordingly, the work must be carried out manually at present, and an automation to completely eliminate the manual operation cannot be accomplished, whereby it is difficult to attain a desirable effect of investment.